A basic principle of network function virtualization (NFV) is to use universal hardware such as x86 and a virtualization technology to bear a large quantity of software having different functions in order to reduce high device costs in a network. NFV may establish a VNF by means of software/hardware decoupling and function abstract such that functions of a network device are no longer dependent upon dedicated hardware and that resources can be fully shared flexibly. In this way, fast development and deployment of new services are implemented, and automatic deployment, flexible scaling, fault isolation, self-healing, and the like are performed based on actual service requirements.
A basic challenge to apply the virtualization technology to network functions is reliability. Many network functions to be virtualized play critical roles in a mobile network architecture. In particular, a core node such as a mobility management entity (MME) includes a large amount of user status information and the user status information is updated frequently, and therefore, any node-level fault is intolerable. However, in an NFV architecture, because network functions are implemented using software, in comparison with a hardware-based implementation solution, it is even more difficult to achieve carrier-class reliability.
In other approaches, a backup mode is primarily used to avoid impact caused by a network node fault. Using the MME as an example, when a fault occurs, user equipment (UE) context information is sent to a backup MME node by means of status synchronization. However, a core node like the MME involves a large amount of fast changing UE context information, and the status synchronization consumes a lot of time and resources. Consequently, fault recovery is slow, and reliability is reduced.